The conchoidal lines are ripple marks arising from
variation in the force causing the breakage. Traversed
by three types of what are known as Wallner Lines,
these resemble hairs crossing the ripple marks and
arise from interaction of the elastic waves with the
progressing crack front. When a crack has to twist,
it generates ‘hackle’ – like erect hairs on a frightened
animal – because it is easier for the crack to break up
than to rotate as one, and this appears like a row of
dagger shapes. As cracks get to very high velocities, they
become unstable and the surface turns misty, eventually
becoming a mass of hackle. The glue-chipped surface
has an array of complex cracks working down into the
thickness of the glass which are known as vents and
appear like dark arms, or the ‘wings’ of a ‘bird’.
Before buying a microscope I had been capturing
images from minerals, fossils and rocks for years using
digital scanners. Some work beautifully as fashion
fabrics but the unreconstructed modernist in me
always had reservations about the wilful application of
imagery to surfaces in architecture. The critic Adrian
Stokes famously reinterpreted early Renaissance, and
later all art, in terms of what he called ‘carving’ and
‘modelling’, the first conjuring form from within, the
latter imposing it from without; my sympathies lay
with the carving tradition. The analogy is tenuous, but
somehow I hope it may prove possible to digitally print
some of these images from glass on to glass. It’s hardly
what Stokes understood by carving, but somehow it
feels like barely an imposition at all.